Climate and fisheries: cause and effect or managing the long and short of it all

Recent developments in understanding the sources of variation in aquatic population behaviours, whether the causes are understood or not, have further diminished the presumption that resource populations can be managed on the basis of catch and effort statistics alone. The requirements for obtaining clear, truly rational understanding of any patterns of change that are caused by climate-driven ocean variability or any subsequent ecological processes are: (1) recognition that at least some basic hypotheses must be examined over a fairly long term, i.e. more than only some short portion(s) of usually cyclic processes; (2) that ecological interactions must be accounted for in a similar, reasonably coherent manner; (3) time-series and information collection must include all the habitat, including all boundaries and their perturbations, as well as specific events and processes that have impacts on local fishery production. It will always be necessary to expect that there are several potentially perturbing processes going on at any one time, but the dominant process will vary in time and space, frustrating applications of simplistic, one-process models. These models tend to overintegrate the effects of many perturbing factors and to underemphasize relative effects of what in specific cases are of potential high impact compared with usual considerations.